1. Field of the Invention
The present invention relates to improved gastrostomy and other percutaneous tubes, and to one-way valves and insertion techniques useful with such tubes.
2. Description of the Prior Art
Certain medical conditions require the continuous or repeated percutaneous introduction to bodily organs or tissues of substances such as nutrients (e.g., glucose) or drugs. This may be accomplished by an appropriate percutaneous transport tube. An example of such a condition is a glycogen storage deficiency which requires the delivery of carbohydrates directly into the stomach. For this purpose a surgical opening ("gastrostomy") is made through the abdominal wall into the stomach. A percutaneous transport tube, referred to as a "gastrostomy tube", is inserted through the opening and used to supply glucose solution or other nutrient directly into the stomach.
A typical prior art gastrostomy tube is on the order of 25 centimeters long and consists of a flexible tubing section, typically 5 to 8 millemeters in diameter, made of a silicone composition that is medically inert. The end which is inserted into the stomach may have a Malecot tip consisting of three or four generally semicircular loops of material which readiate from the end of the tube and join at a tip. The radial loop sections can seat against the interior stomach wall so as to impede the inadvertent withdrawal of the tube. Liquid nutrient passes from the tube into the stomach through the openings between these semicircular loops.
The other end of the tube, which is external to the body, is provided with an enlarged diameter end section for connection to a pump that forces the nutrient through the tube. When nutrient is not being administered, the extending tube section is clamped with a rubber band or mechanical clamp to prevent the outflow of gasses or liquids from the stomach due to the buildup of pressure in the stomach.
Other percutaneous transport tubes are of generally similar design, including a tube of suitable material such as silicone with appropriate retention mechanisms at one or both ends. A number of problems are inherent in such prior gastrostomy or like percutaneous transport tubes. First, a relatively long section of the tube extends outside of the abdominal wall. This is unsightly and uncomfortable. One object of the present invention is to provide a percutaneous transport tube having an outer end which is generally flush with the external abdominal wall.
Another disadvantage is the requirement for clamping a gastrostomy or like tube to prevent the backflow of liquid or gas from the stomach. A further object of the present invention is to provide percutaneous transport tubes include one-way valves which prevent such backflow without the necessity for external clamping. Alternatively, for certain purposes one-way outflow from the body may be required, and the valve may be oriented to permit such outflow.
Another problem is the manner in which the pump is attached to a gastrostomy tube. To simplify such connection, it is an object of the present invention to provide a percutaneous transport tube having an easy to use connector assembly for facilitating pump interconnection. Yet another objective is to provide a connector arrangement which permits the direct insertion of nutrient fluids from a syringe assembly for use in an emergency situation when a fluid pump is not available.
A further shortcoming of the prior art concerns the manner of insertion of a gastrostomy tube into the stomach. Typically this is accomplished by a surgeon who inserts a stylet through the length of the tube and up against the end of the Malecot tip. As the surgeon pushes the stylet and tube through the abdominal wall opening, the force of the end of the stylet elongates the Malecot tip, thereby pulling the semicircular sections into a straight, elongated configuration. When so elongated, the Malecot tip can pass through a small gastrostomy opening into the stomach. When the stylus then is withdrawn, the resiliency of the tube material pulls the elongated sections of the Malecot tip back into semicircular configuration, thereby securing the end within the stomach.
A further object of the present invention is to provide simplified means of gastrostomy or like tube insertion. One such objective is to encapsulate or surround the Malecot or other tip configuration in a capsule or binding of material which dissolves within the stomach. Such arrangement permits percutaneous transport tube insertion without the use of a stylus, thereby simplifying the emplacement procedure.
Some improvements in gastrostomy tubes and stomach intubation and catheter placement systems are known in the prior art. For example, U.S. Pat. No. 3,915,171 to Shermata discloses a gastrostomy tube that uses a pair of retention bulbs which respectively engage the inner stomach wall and the outer abdominal wall. The inner bulb is stiffly flexible, and can be collapsed by a stylet for insertion through a stab wound in the stomach.
The U.S. Pat. No. 3,961,632 to Moossun shows a plastic tube catheter which is placed through the abdomen and stomach walls using a central steel needle that is withdrawn from the plastic tube after insertion. An annular section of the plastic tube is inflated with air to form an interior balloon structure within the stomach. A locking disc is clamped around the platic tube on the outside of the abdomen wall to maintain the catheter in place.
The U.S. Pat. No. 3,253,594 to Matthews et al discloses a peritoneal cannula which uses an annular balloon arrangement to retain the inner end of the cannula in place against the flesh. On the outside of the body, a flange or disc is held against the skin by a threaded locking cap, the position of which can be adjusted axially along the cannula.
The British Pat. No. 1,131,436 to Chirana Zavady Zdravotnicke Techniky discloses a gastrostomy apparatus in which the head at the external end of a tubular body is provided with a tripartite rubber flap valve secured in place by a threaded ring. The tubular body is closed by means of a stopper made of a water-repellent non-toxic material.
The U.S.S.R. Pat. No. 286,138 discloses a stomach fistular pipe having a normally closed valve which is opened by a shaft that extends through the pipe and through the body wall.
None of these patented devices satisfy the above described objectives of the present invention.